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United States Patent | 5,028,377 |
Hendry | July 2, 1991 |
A method and apparatus for injection molding plastic articles with gas-assistance wherein the injected molten plastic is depressurized by a controlled amount prior to gas injection to facilitate the penetration of the gas into the molten plastic within the article-defining cavity of the mold.
Inventors: | Hendry; James W. (Brooksville, FL) |
Assignee: | Ladney; Michael (Mt. Clemens, MI) |
Appl. No.: | 488980 |
Filed: | March 5, 1990 |
Current U.S. Class: | 264/572; 264/161; 264/328.12; 264/328.13; 264/328.7; 264/328.8; 425/812 |
Intern'l Class: | B29C 045/00; B29D 022/00 |
Field of Search: | 264/40.3,328.1,328.8,328.12,328.13,500,572,85,328.7,40.5,161 425/140,546,564,568,812,542,577,149 |
4101617 | Jul., 1978 | Friederich | 264/572. |
4129635 | Dec., 1978 | Yasuike et al. | 264/45. |
4740150 | Apr., 1988 | Sayer | 264/572. |
4830812 | May., 1989 | Kauer | 264/572. |
4855094 | Aug., 1989 | Hendry | 264/40. |
4923667 | May., 1990 | Sayer | 264/572. |
Foreign Patent Documents | |||
48-20023 | Jun., 1973 | JP | 264/328. |